TSP #29 - Teardown, Repair and Experiments of an Agilent 86120B Multi-Wavelength Meter

[@mjthebest7294]

I had the privilege to take apart this exact model and taking the he-ne laser, the optics and the light sensors... it's insane to see it right here on KZbin. In this moment I fired up the laser while watching! Thank you so much for the amazing experience and the memories.

[@oriole8789]

Such a fantastic instrument... kind of hard to believe that it was made so long ago. I kind of get scared whenever I deeply examine an old piece of flagship tech like that, just because of the sheer effort that had to go into its design. Its precision is still impressive so many years later. The CNC machined components, the high resolution VFD, the accurate stepper/encoder.. plus all the logic and theory of operation. Really happy that you were able to fix it, and thanks for the video!

[@GadgetUK164]

Fantastic! Thanks for the vid, and thanks for showing the inner workings of that deflection assembly. Great stuff, love the channel - very educational!

[@redtails]

great video man, you know a lot of stuff that is not only useful for repairing this gear, but also to keep the videos interesting enough to watch on a free day

[@gorak9000]

Sweet, another video already! You know Shahriar, if you ever have too much broken stuff, and not enough time to fix it, my (physical) mailbox is always open, and I haven't run into many things I haven't been able to fix, but clearly your garbage bin is a little more advanced than the ones I have access too. The best thing I've managed to get is a LEADER LCR-745 LCR meter, that was pretty easy to fix. Also found some old HP function generators and power supplies, but they tend not to be broken, just old.

[@nicholasbantell2520]

Great Video. Glad to see your doing videos again. Also looks like it is time to purchase a few more hand tools.

[@stevefriedl6184]

I have a junk box full of ICs and resistors.. Shahriar has a junk box of LASERS. Awesome.

[@alextrofimov7947]

I loved the close-up look on the construction of the device! Easy to perceive details)

[@JimGriffOne]

Yay! I'm watching in 360p because I can't wait for HD. I love your videos! Thanks so much for educating me for free. If I can offer you anything in terms of audio mixing, mastering or editing, then please don't hesitate to contact me so I can pay you back with free services.

[@peterhansen8216]

Sharriar Your videos are excellent and you have great equipment. Thanks

[@christopherleubner6633]

Used to fix things like this way back in the day. Well done ❤

[@andymouse]

" ya gotta love this free space optical stuff "...yes, you do !

[@smbrob]

What is amazing to me is the fact that you did not have to calibrate at all after putting in the new laser.

[@gamccoy]

I always learn a great deal from your videos. I wish you were able to create them more often. While I liked the repair, my favorite part was the discussion about the FP laser operation.

[@redtails]

33:20.. hmm, now I do wonder how this machine is capable of measuring the strength of the signal if the reference signal degrades over-time. You'd have to conclude that the machine either doesn't use the reference meter for dB measurement, or it keeps track of the laser's ageing pattern (not very likely)

[@ronaldlijs]

Great video mate, I love your lab, plenty of expensive stuff there, ideal for what you do! Keep them up!!

[@urbandiscipline88]

This guy deserves an expensive lab like that.

[@megasmart1337]

You are good teaching :)

[@douro20]

I almost got a HeNe laser...from an old handheld barcode scanner...it's amazing they were able to fit the laser and its electronics inside the thing- there was almost no space for anything else!

[@jaa93997]

You have an awesome collection of equipment!

[@eldenchang]

You have some instruments, that I have never heard of. Very interesting video, especially since I do not work with fiber optics Thanks for the repair video.

[@redtails]

15:54.. huh that's an ingenious solution to a quite weird problem

[@JGunlimited]

Cool. Was reading about the LIGO 2016 detection and their method sounds very much (in concept) like what you were demonstrating/describing.

[@douro20]

The motor is actually not a stepper but a very high precision brushless motor. The two large ICs on the bottom board are a chipset from Performance Motion Devices designed to control this type of motor.

[@matthewghali2987]

You do such a great job teaching by example how important it is to use the right tool for the job, the right way, when it comes to electronics and RF and optics. I was surprised to see you go ahead and pull that HeNe without the long screwdriver that you knew was needed. Now I'm afraid to see how you managed to torque the mounting screws back with the new laser. Don't get me wrong, I'm a big fan and really appreciate the videos- it was just a surprising place to see you compromise.

[@CanDoo321]

Thank you for sharing. Makes me wish I had a use for such an instrument

[@rolfdieterklein]

The resolution is amazing, a nice instrument, and great video. On ebay the instrument still has a good price - no wonder.

[@helmuthrendl95]

What for a amazing Lab!

[@AliMirjamali]

I really enjoyed this Optoelectronics class. Thank you very much for the video. It is a pity that the Agilent 86120B was not able to zoom into 1305nm or 1541nm spectrum.

[@Thesignalpath]

Yes, I don't know why it doesn't have that ability. It obviously can detect the individual tones...

[@redtails]

22:08 I don't understand this bit.. the number is lower than the 1999 laser? implying the amount of light is less? or am I missing something?

[@aserta]

One thing you could of had done and i always keep a spare set on hand just for that kind of a pickle. Is to take your screw driver tip and cut a slot in the top, then using a simple straight line screwdriver that fits through the hole drive the bit via that slot.

[@AlexandreJasmin]

Cats sit on the weirdest spots

[@Fake0Name]

Are the mirrors on the spinning wheel corner retroreflectors? They kind of look like it, and that would explain how it handles the change in angle as a function of the wheel rotating.

[@berndnebendahl6794]

you are right, it would not work with flat mirrors

[@Coolkeys2009]

Nice video, I wanted you to shine the output of those HP lasers through some prisms. Then I remembered there infra red, never mind the fact they might blind you.

[@redtails]

12:00 I wonder how they even got it in there

[@Dagosaatana]

Hey Shahriar! Thanks for the great video! You seem to have a lot of fiber optics stuff, what do you do with them :)?

[@linjipeng]

hi there, thanks you so much for sharing this great video. I saw a Error 34 Battery Failed. But when i open the box with your instruction, i cannot find the battery. I wonder if you can kindly point out where i can find this battery. Thanks

[@redtails]

3:27 CAT

[@Megabean]

Very cool, why does it have such a fiberoptic cable inside? Does this affect the performance in anyway? I'm a Laymen :P

[@Thesignalpath]

They must have used an off-the-shelf fiber cable. The length has no effect on the performance because it is very short. It would have to be > 500 meters before it causes any significant losses. Cutting a fiber optic cable shorter is very difficult as it needs to be spliced.

[@Megabean]

TheSignalPathBlog I see, I guess the cost of the extra cable wasn't a huge concern for them.

[@OneCoolDude08]

I was wondering the same thing. In oscilloscopes they have the same type of thing called a delay line. Creates a very short delay, but long enough to catch the leading edge of a waveform. In this case I don't know if that is what it is.

[@Thesignalpath]

OneCoolDude08 This fiber is directly at the input. Its length does not matter since the length of the fiber on the outside of the unit is arbitrary.

[@OneCoolDude08]

TheSignalPathBlog Thanks for the info. Love your channel. Thanks for making the videos!! Better than anything on television.

[@yaghiyahbrenner8902]

what type of cat is that. ?

[@Thesignalpath]

He is a Russian Blue mix. Although, nobody knows and he isn't talking about it.

[@billarkin8446]

What is that paper (pad)that you use to wipe the fiber to know that it is clean

[@Kennynva]

You need a ratcheting wrench...so it will turn without taking the wrench out everytime to move the torx bit..

[@yjwukt88]

I acquired a broken Anritsu MF9630A Optical Wavelength meter a while ago. It displayed "Error 101" at power up. Could it also be a weak He-Ne laser? The iodine stabilized laser probably needs more power to operate properly. Any suggestion on how to obtain a service manual?

[@DrenImeraj]

I thought KZbin prohibits pornography. Awesome video, you are a legend.

[@redtails]

10:01 very helpful cat

[@BarriosGroupie]

That's quite a lab you have: Is it yours, and are you self-employed?

[@Thesignalpath]

This is my own personal lab, and no I am not self-employed. I have been buying and repairing equipment for 15 years. It takes a lot of time and effort to put together a lab. I am fortunate to have some disposable income to spend on such things. And I try to share my fortune by producing these videos on my spare time and making them available for free to everyone. The free dissemination of knowledge should be everyone's goal!

[@hinz1]

TheSignalPathBlog Personal lab in the form of "rich company owns lab and you can do there what ever you want" or personal "you bought/stole/found etc everything inside and thereby own it" lab? If the latter is true, you must be really rich or/and very lucky. I can only afford the old HP(4 digit) stuff, and even some of that is still freaking expensive, like the HP 8566B SA

[@aiden1015]

TheSignalPathBlog and he's using "some" quite modestly.

[@Thesignalpath]

douro20 That is true. However, The Signal Path Blog is an entirely separate entity from my work. It is my personal endeavor and for educational purposes only.

[@DavidMG99]

👍👍

[@lechulsk4845]

Basic He-Ne laser yes. Maybe for you it's basic but not for your viewers... Your videos are really great. I'm an engineer too but... it's not my league

[@africanelectron751]

Good to see more of your excellent videos although a good deal fly's way above my head i make sure to google everything i don't understand

[@XFolf]

error 632... the integer value of a HE/NE Laser, true value 632.8nm... for whatever reason, I had a laugh over this.

[@XFolf]

XFolf omg.... I'm twitchy with the tab/enter combo... *facepalm* anyway.. that's what it should have been called.. if the programmer had had a sense of humor.

[@MrMac5150]

You always luck out..

[@First2ner]

don't point lasers at camera, I have seen them kill several px on sensor